In general, an electric bulb or a fluorescent lamp is commonly used as an indoor or outdoor lighting lamp. However, the electric bulb or the fluorescent lamp has a short life span, so that it should be frequently changed. Moreover, a conventional fluorescent lamp degrades due to the time it is used. As a result, often its illuminance is gradually decreased.
In order to overcome such problems, a lighting apparatus is now being developed by using a light emitting device (hereinafter, referred to as LED). The LED is easy to control and has a rapid response speed, high electro-optic conversion efficiency, a long life span, low power consumption and high luminance. The LED is also used to create emotional lighting.
Meanwhile, the shapes of most of lighting apparatus to which the LED is applied are limited in accordance with the structure of the space in which the lighting apparatus is installed. Therefore, the field of use of the lighting apparatus or a kind of a space in which the lighting apparatus is used is increasing.